Charge voltage of Ni MH battery

Charge voltage of Ni MH battery

The daily use of 1.2V nimh battery full voltage is usually 1.4V, and the termination voltage is 0.9V. This means that Ni MH power battery is inconvenient to use when discharging to 0.9V and should be charged. Therefore, 0.9V is both the termination voltage of discharge and the starting voltage of nimh battery charging. In practice, since there are some small currents in Ni MH batteries after 0.9V, it is also feasible to set the initial voltage to 0.8V for some nimh batteries. 

The full voltage of Ni MH battery is about 1.4V, which can be regarded as its highest voltage, but the individual battery also depends on the specific charging mode.

One case is to charge at a constant voltage, and the older mode of charge is still set, usually set to 1.4V, but the consequence may be that the battery may not have enough to reach the 1.4V. In this case, the termination voltage of the Ni MH battery is not the full voltage of the nimh battery.

The above defects are mainly caused by charging current, and large current charging may not be full at 1.4V. From the charging curve, some of the nimh battery charged with 1C can reach 100% of the voltage to reach the destination 1.53V, and then turn down to near the voltage of 1.4V, so 1.53V becomes the highest charging voltage, and the nimh battery charger often passes this feature to set the turning point voltage to be set as charge cut-off time.

The comparison of charge voltage between large current and small current charge is that the small current can be filled with electricity at lower voltage, and the charge can still raise the voltage slowly after full electricity. On the contrary, the large current above 1C will continue to charge under full electric state, and the voltage will not rise. Therefore, when the voltage reaches a certain height (such as 1.36V), it is reasonable to use 0.3C for small current charging.